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/*
* arch/sh/lib/csum_parial.c
*
* This file contains network checksum routines that are better done
* in an architecture-specific manner due to speed..
*/
#undef DEBUG
#include <linux/config.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <asm/byteorder.h>
#include <asm/uaccess.h>
static inline unsigned short from64to16(unsigned long long x)
{
/* add up 32-bit words for 33 bits */
x = (x & 0xffffffff) + (x >> 32);
/* add up 16-bit and 17-bit words for 17+c bits */
x = (x & 0xffff) + (x >> 16);
/* add up 16-bit and 2-bit for 16+c bit */
x = (x & 0xffff) + (x >> 16);
/* add up carry.. */
x = (x & 0xffff) + (x >> 16);
return x;
}
static inline unsigned short foldto16(unsigned long x)
{
/* add up 16-bit for 17 bits */
x = (x & 0xffff) + (x >> 16);
/* add up carry.. */
x = (x & 0xffff) + (x >> 16);
return x;
}
static inline unsigned short myfoldto16(unsigned long long x)
{
/* Fold down to 32-bits so we don't loose in the typedef-less
network stack. */
/* 64 to 33 */
x = (x & 0xffffffff) + (x >> 32);
/* 33 to 32 */
x = (x & 0xffffffff) + (x >> 32);
/* add up 16-bit for 17 bits */
x = (x & 0xffff) + (x >> 16);
/* add up carry.. */
x = (x & 0xffff) + (x >> 16);
return x;
}
#define odd(x) ((x)&1)
#define U16(x) ntohs(x)
static unsigned long do_csum(const unsigned char *buff, int len)
{
int odd, count;
unsigned long result = 0;
pr_debug("do_csum buff %p, len %d (0x%x)\n", buff, len, len);
#ifdef DEBUG
for (i = 0; i < len; i++) {
if ((i % 26) == 0)
printk("\n");
printk("%02X ", buff[i]);
}
#endif
if (len <= 0)
goto out;
odd = 1 & (unsigned long) buff;
if (odd) {
result = *buff << 8;
len--;
buff++;
}
count = len >> 1; /* nr of 16-bit words.. */
if (count) {
if (2 & (unsigned long) buff) {
result += *(unsigned short *) buff;
count--;
len -= 2;
buff += 2;
}
count >>= 1; /* nr of 32-bit words.. */
if (count) {
unsigned long carry = 0;
do {
unsigned long w = *(unsigned long *) buff;
buff += 4;
count--;
result += carry;
result += w;
carry = (w > result);
} while (count);
result += carry;
result = (result & 0xffff) + (result >> 16);
}
if (len & 2) {
result += *(unsigned short *) buff;
buff += 2;
}
}
if (len & 1)
result += *buff;
result = foldto16(result);
if (odd)
result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);
pr_debug("\nCHECKSUM is 0x%x\n", result);
out:
return result;
}
/* computes the checksum of a memory block at buff, length len,
and adds in "sum" (32-bit) */
unsigned int csum_partial(const unsigned char *buff, int len, unsigned int sum)
{
unsigned long long result = do_csum(buff, len);
/* add in old sum, and carry.. */
result += sum;
/* 32+c bits -> 32 bits */
result = (result & 0xffffffff) + (result >> 32);
pr_debug("csum_partial, buff %p len %d sum 0x%x result=0x%016Lx\n",
buff, len, sum, result);
return result;
}
/* Copy while checksumming, otherwise like csum_partial. */
unsigned int
csum_partial_copy(const unsigned char *src, unsigned char *dst, int len, unsigned int sum)
{
sum = csum_partial(src, len, sum);
memcpy(dst, src, len);
return sum;
}
/* Copy from userspace and compute checksum. If we catch an exception
then zero the rest of the buffer. */
unsigned int
csum_partial_copy_from_user(const unsigned char *src, unsigned char *dst, int len,
unsigned int sum, int *err_ptr)
{
int missing;
pr_debug
("csum_partial_copy_from_user src %p, dest %p, len %d, sum %08x, err_ptr %p\n",
src, dst, len, sum, err_ptr);
missing = copy_from_user(dst, src, len);
pr_debug(" access_ok %d\n", __access_ok((unsigned long) src, len));
pr_debug(" missing %d\n", missing);
if (missing) {
memset(dst + len - missing, 0, missing);
*err_ptr = -EFAULT;
}
return csum_partial(dst, len, sum);
}
/* Copy to userspace and compute checksum. */
unsigned int
csum_partial_copy_to_user(const unsigned char *src, unsigned char *dst, int len,
unsigned int sum, int *err_ptr)
{
sum = csum_partial(src, len, sum);
if (copy_to_user(dst, src, len))
*err_ptr = -EFAULT;
return sum;
}
/*
* This is a version of ip_compute_csum() optimized for IP headers,
* which always checksum on 4 octet boundaries.
*/
unsigned short ip_fast_csum(unsigned char *iph, unsigned int ihl)
{
pr_debug("ip_fast_csum %p,%d\n", iph, ihl);
return ~do_csum(iph, ihl * 4);
}
unsigned int csum_tcpudp_nofold(unsigned long saddr,
unsigned long daddr,
unsigned short len,
unsigned short proto, unsigned int sum)
{
unsigned long long result;
pr_debug("ntohs(0x%x)=0x%x\n", 0xdead, ntohs(0xdead));
pr_debug("htons(0x%x)=0x%x\n", 0xdead, htons(0xdead));
result = ((unsigned long long) saddr +
(unsigned long long) daddr +
(unsigned long long) sum +
((unsigned long long) ntohs(len) << 16) +
((unsigned long long) proto << 8));
/* Fold down to 32-bits so we don't loose in the typedef-less
network stack. */
/* 64 to 33 */
result = (result & 0xffffffff) + (result >> 32);
/* 33 to 32 */
result = (result & 0xffffffff) + (result >> 32);
pr_debug("%s saddr %x daddr %x len %x proto %x sum %x result %08Lx\n",
__FUNCTION__, saddr, daddr, len, proto, sum, result);
return result;
}
// Post SIM:
unsigned int
csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst, int len, unsigned int sum)
{
// unsigned dummy;
pr_debug("csum_partial_copy_nocheck src %p dst %p len %d\n", src, dst,
len);
return csum_partial_copy(src, dst, len, sum);
}
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